The lighter side of the challenging Advanced Placement program at California's El Cajon Valley High School brightens a student. (AVID Center)

More than 25 percent of first-year college students need remedial courses. Concern about the ability of American high-school graduates to handle college-level work has led some schools to offer Advanced Placement (AP) and International Baccalaureate (IB) programs. Engaging students in more challenging coursework appears to boost learning and achievement, although there is little research on the effects of AP and IB programs. Higher-income students are much more likely to be offered AP and IB classes or other challenging learning experiences than students from disadvantaged educational or socioeconomic backgrounds. Over the past decade, most school reform has focused on the elementary grades, but a growing number of states are now concentrating on improving the college readiness of their high-school students. But critics say the effort is wasted if younger students aren't given adequate preparation for high school.